Effects of superimposed pulse bias on TiN coating in cathodic arc deposition

Orthogonal designs are used to investigate the main factors when doing experiments in which pulse bias is superimposed on d.c. bias during cathodic are deposition of TiN. Pulse peak, duty cycle, frequency, direct voltage, are current and pressure all are investigated when coating TiN on HSS substrates. Roughness, surface micrograph, microhardness and thickness are tested. By analysis of variance, it is shown that pressure and frequency are the main factors. R-a and droplet density of the film with (d.c. + pulse) bias decrease. A simple explanation for the result is suggested.

Low field electron emission from nanoclustered carbon grown by cathodic arc

Nanocluster carbon films grown using a cathodic arc process at room temperature in the presence of background gases such as helium are found to be good electron emitters. The variation in the surface morphology and the corresponding emission characteristics of the films with change in helium partial pressure (5×10-4 to 50 Torr) during film growth are reported. The effect of helium partial pressure on clustering was studied for films grown at nitrogen partial pressures of 10-4 and 10-3 Torr. The surface morphology of the films varied from smooth through clusters (with sizes 50-200 nm) to fibrous films. The threshold field varied from 1 to 10 V/μm for an emission current density 1 μA/cm2.